Process of recovering gold.



1 1. ALLING. PROCESS OF REC UVERING 60H)?" APPLICATION FILED OCT. 18, 1910- RENEWED AUG. 18,1911.)

1,207,261. Patented Dec. 5,1916;

INVENTOR ATTORNEY UNITED sTATrEsPATENT OFFICE- JAMES H. .ALLING,

OF COLUMBIA, CALIEORNIA, ASSIGNOR OF ONE-HALF T FRANCIS M. WEIGHT, 0]? SAN FRANCISCO, CALIFORNIA.

Specification of Letters Patent.

Application-filed October 18, 1910, Serial No. 587,676. Renewed August 18, 1911. Serial No. 644,889.

I b (1 whom "it may concern Be it known that I, Janus H. Aniline, a

. citizen of the United States, residing at Columbia, in the county of Tuolumne and State of California, have invented new and useful Improvements in Processes of Recovcring Gold, of which the following is a specification.

able time and labor. These processes cannot be used simultaneously with the ordinary processes used for recovering particles of gold of larger size, such aspassing the pulp containing said particles down sluice boxes formed with riiiics or amalgamating plates, or passing it through centrifugal separators. In other words, these processes cannot be used simultaneously with the processes of re covering gold in large particles which take advantage of its great density. Also in United States Letters Patent No. 947,957, issued-to me Feb. 1,1910, I describe and claim a process of recovering comparatively large particles of gold coated with an oxid, said process consisting of the electric decomposition of a chlorin compound to liberate nascent chlorin and at the same time maintain the mercury in a fit condition for amalgamation. In by far the greater number of mines the gold particles are of all sizes, varying from easily visible particles to particles which can be seen only by the microscope; also in many cases some of the gold is covered with an oxid coating. Heretofore, for the recovery of such gold it has been necessary to treat the material containing the gold atseparate times by two operations, by one'of which the coarser gold is recovered, and by the other, of which are treated the tailings, after the cQa ser gold has been extracted, the latter process being slow and expensive. Moreover, when treating by the process in my patent ref'grred'to papti cles of gold having oxid coatings, the nascent chlorin attacks not only said coatings but also the fine microscopic particles having no oxid coatings, and dissolves them, forming trichlorid of gold, from which the gold can only be recovered by slow and expensive processes.

Now the object of my present invention is to provide a process in the operation of which all of said particles, namely, comparatively large particles of clean gold, particles with an oxid coating, and clean microscopic particles of float gold, can be recovered sinuiltaneously, and as rapidly as coarse gold is at present recovered in the ordinary sluice PatentedDec. 5,1916.

boxes, thus dispensing with the necessity of large and expensive plants, involving a great expenditure of time and labor.

In the accompanying drawing, 1 indicates a sluice box composed of wood, the bottom2 of which sluice box is thoroughly impregnated with asphaltum by dipping therein and the sides 3 are painted with asphaltum paint. The purpose of this is to render said bottom and sides non-conductin The bot tom of the sluice box is formed with pockets 4. The anodes 6 are all electrically connected by a conductor 8 toa positive-pole of a source 9 ofelectricity and the screws 7 areall so connected by; a conductor 10 to the' negative pole of said source. A launder 11 is; 1 isedj to feed the material to the-sluice bait A-receptacle 12 is also provided to feed a, salt solution to said launder.

The following description of the nature of my improved process will be confined to its use for recovering gold, it being understood that the process-may be also applied to the recovery of other precious'metals.

The pulp containing theauriferous ma-' terial is dischar ed on to the launder 11 and therewith is fe from thlt receptacle 12,2

small quantityof a; solutio' of 'con mon salt I prefer common salt 0 a, c'count' of its cheapness, but other elilori'i compounds Screwed through the sides might be used, as for instance, potamium chlorid. Sea water may be used as the salt solution if desired. This pulp, mixed with the salt solution, is caused to pass in succession between the several anodes and corresponding cathodes of the apparatus, and,

and salt solution flows alternately. In pass- 111g beneath an anode, the mixture flows through an electrolytic region, the electric current flowing from the lower surface of the anode to the mercury in the pocket, and

between each pair of anodes, the mixture flows through a non-electrolytic region, through which no electricity passes. I11 flowing through the first of the above electrolytic regions, beneath the first anode, the sodium chlorid and waterare byfelectrolysis.

decomposed, the sodium chlorid into sodium and chlorid and the water into hydrogen and hydroxy the sodium and hydrogen appearing at the negative electrode and'the chlorin and hydroxyl at the positive electrode. On account of the momentum of the mixture, part only of the sodium thus de-, posited unites with the mercury in the oathode, the remainder escaping therefrom. Such is also the case with the hydrogen, but the part of the hydrogen'which is collected at the cathode is proportionately less, on account of its much smaller specific gravity. Sodium hydrogen amalgam is thus formed at the cathode. The chlorin and hydroxyl do not of course appear in the electrolyte between the anode and cathode, but only at the anode, at which chlorin appears in its nascent condition. The nascent chlorin given off at the surface of the anode attacks the fine microscopic particles of gold in the pulp and forms trichlorid of gold.

This formation'f'of trichlorid of gold, however, cannot ake place in the region through which electrolysis is taking place,

being prevented by the current of electricity passing theret hrough, which tends to decom pose trichlorifld of gold. It only takes place outside ofsalid region, or, at the most, at the boundaries thereof, where the electric current is ndt strong enough to prevent the chemical combination of nascent chlorin with the microscopic particles of gold. Some of it takes place on the front side of the anode, toward which the mixture is flowing, but the greater part of it takesplace on the rear side thereof, and particularly in the=non-electrolytic region between said anode and the next succeeding anode. From the above explanationit will be seen that it is very important that the lower rt of the anode should be well covered wit the mixtureboth at the front and back, so that the nascent chlorin cannot escape into the at- Biosphere,- before performing'its duty upon the particles of gold. It is also preferable not to supply too much waterto the stream. ,For'instance, a streamconsisting of per cent. of pulp and 40 percent. of water will give better results than one consisting of 40 per cent. of pulpandifil) per cent of water. The sodium and hydrogen. which are not deposited permanently upon the cathode, but

are washed away therefrom by the force of the stream of -water and vpulp, pass into the next succeeding. nonelectrolytic region.

. Thereupon the sodium-unites with the hydroxyl, previously liberated by electrolysis,

combines with any greasy coating of the -metallic particles of the 'pulp', and the h drogen unites .with the chlorin previous y liberated, and which has not formed trichlorid of gold, and forms hydrochloric acid.

The hydrochloric acid and the caustic soda immediately unite to form common salt and waters The trichlorid of gold which has beeni thusfl formed is now carried with the stream ofpulp between the next succeeding BlBUiQI'OdGQ OIQdf it has been formed in the front of the anode, it is carried between the same electrodes as before referred to. the electroyltic action of the electric current and formscaustlc soda, which chemically" between said electrodes, the trichlorid of gold is now decomposed, and gold is de mercury cathode. the trichlorid-of g0ld,',the chlorin appears again at the positive electrode in a nascent condition, and can attack the particles of fine gold arriving thereat, and again form trichlorid of gold, from .which gold is 'obposited upon, and amalgamated with, the In' the decomposition of l tained in the same way as in that already described, or it may escape, and form,-firs:t, hydrochloric acid, and then by the union of hydrochloric acid and caustic soda, a solution of common salt.

While experiments which have been made indicate'that the above are the chemical reactions that occur, yet the precise nature of these reactions is not of importance, it being known positively only that the'material to be treated should pass alternately through electrolytic and non-electrolytic regions. aln

an electrolytic region take place the defcom; x position of salt and trichlorid of--.gold' it has been already formed) with the deposition of gold at the cathode and the libera-- tion of chlorin at the anode. In a non-electrolytic region take place recombination of part of the constituent elements thereof, and the combination of said chlorin with gold freshly supplied. However, the only essential feature of the process is that the pulp should be subjected alternately to a condition of electrolysis, and a condition in which. electrolysis 1s not present, so that the constituent elements can'again recombine.

limited thereto, as the pulp might flow con tinuously in a stream through which. an in- 'ter'mittent current is passed, the intervals b dtween thefl'passages of the current being suli'nziently; long. to permit recombination of the constituent elements.

I I amaware that E. P. Thompson in his .United ,StatesLetters Patent No. 317,245, dated May 5., 1885,-.discloses a method of recovering old from auriferous pulp by:

, liberating c lorin from its compoundaas conmion salt ivy-electrolysis, then dissolving the gold by the liberated chlorin, and finally depositing by electrolysis the gold from-the trichlorid of gold thus formed;

slab that J. H. Haycraft, in his United States Letters Patent No, 579,872, dated Mar. 30, 1897, 'discloses a similar method. But/I make no claim to the process herein described considered merely as the production of a succession of chemical changes.

The object of my invention is to provide a process by which fine or microscopic gold can-be recovered, simultaneously and in the same-operation, with comparatively large particles of clean gold, and also with coated particles of gold, if such exist, as fast as the auriferous pulp can be delivered from stamp mills or the like, and without the necessity of employing large and expensive apparatus, or operating valves, or removing the material bodily from one vessel to an other, or in fact devoting any attention Whatever to the operation of the process after once properly starting it. My process is therefore distinguished from those of Thompson and Haycraft in that the mixture is caused to flow in a continuous stream, the worthless ga-ngue being removed continuously from the end thereof as the mixture is -...si,1pdplied continuously to the beginning-of lsal ,pass through a large number of pairs of streamga-and said stream is caused to alternatin electrolytic and non-electrolytic IB'gIOIIS; ,y-the inclusionin my process of tlmfirst step above mentioned I am enabled as in tsluice boxes 'or in centrifugal sepainthe same ciperation to combine the present process with the well known process of recovering large free particles of gold by taking advantage ofthe great density of gold,

' tutors, and also-to treat the material very rapidly, as fast as 'it can be supplied by sta n) millsfor the like, getting rid of the 1Wo'rt -less gangue While retaining the recovcred gold,- and by including the second above mentioned-step of the above process, I am mitany the gold to escapeysince, in

the first non-clcclrolytic region, fine particlcs of gold escape the action of nascent chlorin, and are therefore not deposited on passing through the next electrolytic region, such particles are almost certain to be dissolved by the nascent chlorinin the second nonelectrolytic region or in the subsequent non-electrolytic regions.

A remarkable advantage of my present process is that the more minute the gold is and therefore the more diflicult to recover by ordinary sluice box or continuous flow methods, the more easily it is recovered by my present method,'which is also a continuous flow method, since the more readily is it acted upon by the nascent chlorin to form trichlorid of gold.

Since this process can be used in combination with the ordinary mechanical process of recoveringgold suitable particularly to particles of visible size or thereabout, the latter process being assisted by the formation of sodium hydrogen amalgam, and also with my patented process above referred to for recovering coated gold, it provides, with said processes, a highly advantageous method of recovering gold, since by the simultaneous operation ofz-these processes particles of all sizes are recovered, and thus a com leterecovery of the gold from the pulp alkali, such as chlorid of lime, to counteract the effects of the acid on the sodium.

For the sake of brevity only, the process as claimed will be confined to that of recovering gold, it being understood that the same process may be applied to other precious metals.

I claim:- 1. The process of recovering gold from auriferous ulp, which'consist's in mixing ,the pulp w th an aqueous solution of common salt, passing said mixture once only in a continuous stream through a series of pa rs of regions, the first region of each pair being electrolytic and the second non-electrolytic, continuously su plyingthe' -I nixture to the beginning 0 'saidstream, continuouslyremoving the worthless 'gangue from the end thereof, and collecting the gold from the negative electrodes of said electro-:

'lytic regions, substantially as described-Q 2, Theprocess of recovering gold from auriferous pulp, which consists m mixing continuously supplying the mixture to the beginning of said stream, continuously removing the worthless gangue from the end thereof, and collecting the gold from the cathode region, substantially as described.

3. The process of recovering gold from auriferous pulp, which consists in mixing the pulp with a. solution of a chlorin compound dccomposablc by an electric current, passing said mixture once only in a continuous stream through a series of pairs of regions, the first region of each pair being electrolytic and the second non-electrolytic, continuously supplying the mixture to the beginning of said stream, continuously removing the, worthless gangue from the end thereof, and collecting the gold from the negative electrodes of said electrolytic re gions, substantially as described,

4. The process of recovering gold from auriferous pulp, which consists in mixing the pulp with a solution of a chlorin 0111 pound decomposable by an electric current, causing said mixture to flow in a continuous stream, repeatedly subjecting the mixture while flowing in said stream to the electrolytic action of an electric current at intervals sufficiently long to' permit chemical combination of the liberated nascent chlorin and gold in the mixture, continuously sup plying the mixture to thebcginning of said stream, continuously removing the worth less gangue from the end thereof, and collecting the gold from the cathode region, substantially as described.

5. The process of recovering gold from auriferous pulp, which consists in mixing the pulp with an aqueous solution of common salt, passing said mixture once only in a stream through a series of alternate elec trolytic and non-electrolytic regions so that the Whole of said mixture has free access to the cathodes in the electrolytic regions, supplying the mixture to the beginning of said stream, removing the worthless gangue from the end thereof, and collecting the gold from the negative electrodes of said electrolytic regions.

6. The process ofrecovering gold from auriferous pulp, which consists in mixing the pulp' Wlth an aqueous solution of c0mmon salt, causing said mixture to flow. in a stream, repeatedly subjecting the mixture while flowing in said stream tojthe electrolytic action of an electric current at intervals sufliciently long to permit chemical combination of the liberated nascent chlorin and gold in the mixture, and also repeatedly directing the mixture while so flowing in said stream into close proximity with amalgamating surfaces, supplying the mixture to the beginning of said stream, removing the worthless gangue from the end thereof, and collecting the gold from the cathode region.

7. The process of recovering gold from aurifcrous pulp, which consists in mixing 5 the pulp with a. solution of a chlorin come pound decomposable by an electric current, passing said mixture once only in a stream through a series of alternately electrolytic and non-ele ctrolytic regions so that said mixture has free access to the cathodes in the electrolytic regions, supplying the mixture to the beginning of said stream, removing the worthless gangue. from the end thereof, and collecting the gold from the negative electrodes of said electrolytic regions.

8. The process of recovering gold from auriferous pulp, which consists in mixing the pulp with a solution of a chlorin compound decomposable by an electric current, causing said mixture to flow in afstream, repeatedlyw subjecting the mixture while flowing in said stream to the electrolytic action of an electric current at intervals suliicientl y long to permit chemical combination of the liberated nascent chlorin and ,gold in the mixture, and also repeatedly directing the mixture while so flowing in said stream into close proximity with amalgamating surfaces, supplying the mixture to the beginning of the stream, removing thei worthless gangue from the end thereof, and collecting the gold from the cathode region.

9. The process of recovering gold'from auriferous pulp, which consists in mixing the pulp with an aqueous solution of common salt, causing said mixture to flow by gravity only in a stream thimugh a series of alternate electrolytic and nQn-electro: "1.10 lytic regions supplying tlfe mixture to the 1 beginning of said stream, removing the worthless gangue from the end thereof, and collecting the gold from the negative electrodes of said electrolytic regions.

10. The process of recovering gold from auriferous pulp, which consists in mixing the pulp with an aqueous solution of common salt, causing said mixture to flowby gravity only in a stream, repeatedly subjecting the mixture while flowing in said stream to the electrolytic action of an electric cur rent at intervals sufiiciently long to per chemical combination of the libera nascent chlorin and gold in the mixt h, supplying the mixture to the beginning 10f said stream, removing, the worthless gan 1e from the end thereof, and collecting the gold from the cathode region.

11. The process of recovering gold fr auriferous pulp, which consists in mixing the pulp with a solutionof a chlorin compound decomposable by an electric current,

causing said mixture to How by gravity only in astream, repeatedly subjecting the mixture while flowing in said stream to the electrolytic action of an electric current at intervals suificiently long to permit chemical combination of the liberated nascent chlorin and gold in the mixture, supplying the mixture to the beginning of said stream, removing the worthless gangue from the end cathode region.

13. The process of recovering gold from auriferous pulp, which consists in mixing thereof, and collecting the gold from the the pulp with an aqueous solution of common salt, passing said mixture once only in a' continuous vertically undulating stream through a series of pairs of regions, the first region of each pair being electrolytic and the second non-electrolytic, and the cathodes of said electrolytic regions being at the bottoms of said undulations, continuously supplying the mixture to the beginning of said stream, continuously removing the worthless gangue from the end thereof, and collecting the gold from the negative electrodes ofsaid electrolytic regions,'substantially as described.

14a The process of recovering gold from auriferous pulp, which consists in mixing the pulp with a solution of a chlorin compound decomposable by an electric current, passing said mixture once only in a continuous vertically undulating stream through a series of pairs of regions, the first region of each pair being electrolytic and the second non-electrolytic, and the cathodes of.

said electrolytic regions being at the bottoms of said undulations, continuously supplying the mixture to the beginning of said stream, continuously removing the worthless gangue from the end thereof, and collecting the gold from the negative electrodes of said electrolytic regions, substantially as described.

15. The process, whichconsists in mixing metalliferous pulp with a solution of a compound decomposable by an electric current into components, one of which can diswlve the metal and be separated therefrom by electrolysis, causing said mixture to flow in a-stream through a series of alternate electrolytic and nonelectrolytic regions, so that the whole of the mixturehas free access to the negative electrodes of said electrolytic regions.

16. The process which consists in mixing pulp containing a metal soluble in an aqueous or similar solution with a solution of a compound decomposable by an electric current into components, one of which can .dissolve the metal and be separated therefrom by electrolysis, causing said mixture to flow by gravity only in a stream through a series of alternate electrolytic and non-electrolytic region s, supplying the mixture to the beginning of said stream, removing the worthless gangue from the end thereof, and collecting the metal from the negative electrodes of said electrolytic regions.

1.7. The process which consists in mixing pulp containing a metal soluble in an aqueous or similar solution with a solution of a compound decomposable by an electric current into components, one of which an dissolve the metal and be separated thereirom 'by electrolysis, passing said mixture once only in a continuous vertically undulating stream through a series of pairs of regions,

the first region of each pair being electrolytic andthe second non-electrolyticpnnd the cathodes of 'said electrolytic regions *begions, substantially as. described.

'18. The process of recovering precious metals which consists in mixing metalliferous pulp with a suitable electrolyte solution, causing said mixture to flow in a continuous stream, passing an electric current-through the mixture to decompose said solution', then permitting the ions separated by the elec trolysis to chemically rea'pt upon the pulp,

and then passing an electric current through the pulp so acted on to deposit the metal upon the cathode, while continuously sup plying fresh mixture'at the beginnlng of the stream to be so treated and continuously removing worthless material at the en thereof.-

19'. The process of recovering a metal soluble in an aqueous or similar solution which consists in mixing pulp containing the metal with a suitable electrolyte solution, causing said mixture to flow in a continuous stream,

passing an electric current through the mixture to decompose said solution, then permitting the ions separated by the electrolysis to chemically react upon the pulp, and

then passing an electricjcurrent through the I my hand in the presence of two subscribing pulp so acted on to deposit. the metal upon witnesses. the cathode, While continuously supplying fresh mixture at the beginning of the stream JAMES H. ALLING. 5 to be so treated and continuously removing Vitnesses: Y

worthless n'mterial at the end thereof. F. M. WRIGHT,

, In testimony whereof I have hereunto set D. B. RICHARDS. 

